Solved my problem. Here's what I've learned, in case it help someone else.
It turns out that "Stealth VPN" was what I needed to get around the Sonicwall system my public library uses. I succeeded in connecting with Open VPN via port 443 (SSL).
I searched for VPN providers that supported "Stealth VPN" and Linux. VPN Reactor was highly recommended. My other finalists were Astrill, TorGuard, and AceVPN.
AceVPN allowed me to purchase a one month subscription (free trials are available if you jump through a few hoops) and was only US $5.95. Bought a month. (Consensus seems to be that free VPNs are worthless.)
Installed AceVPN on Crunchbang Linux Statler & Waldorf (Debian Old Stable & Stable/Wheezy). Since Crunchbang has Network Manager & OpenVPN installed by default, configuration was quite simple.
Tried using three different AceVPN sites/servers. First worked fine. Second timed out. Third was fine.
Tip: Do the installation on a network where VPN providers are not blocked by IP address or Deep Packet Inspection. After install, use on other nets.
Observations about AceVPN:
-- Negative review on www.bestvpn.com. I searched for other reviews and they were generally positive. My experiences have been generally positive. YMMV.
-- AceVPN accepts payment via PayPal and Google. No automatic renewal. Email to customer 7 days before expiration. Premature renewals are extended to include unused days. Cheaper for quarterly, half yearly, and yearly. Seemed businesslike.
-- Documentation is sparse, but adequate. Probably not optimal for computer newbie, but I had no problems.
-- I bought the cheaper "Premium" tier. Limited to 50 GB. More than adequate for my modest needs.
-- Did not use customer support, forums, or knowledge base. No need.
-- Only tried Linux. Supports Windows, Linux, Mac, iOS, Android, routers, etc.
-- Speed seems adequate. I watched about 30 minutes of streaming video from twit.tv while doing other things on the computer. No issues.
I'm a happy camper. I can use my comfortable public library's WiFi securely for less than US $6 a month. Should be usable at most public WiFi sites that are reasonably open.